i'm using ffmpeg to 'rebuild' mp3s by copying the audio stream to a new file while discarding most of the metadata - the problem i'm having is that the LAME tag is also discarded and i want to keep that
basically i want to remove all of the 'fluff', such as artist, title, comments. cover art, etc., but keep everything that an mp3 requires and that is useful to the decoder
i've been playing with combinations of the following and the LAME tag is always trash-canned, but if i adjust to keep the tag, then other stuff i don't want (artist, etc.) is also retained...
-hide_banner -loglevel warning -i 'in.mp3' -ignore_unknown -map 0:a -map_metadata -1 -codec:a copy -bitexact 'out.mp3'
i'm rebuilding the mp3s because i'm not intimately familiar with the format, so i'm guessing that using ffmpeg to copy to a new file is the way to go, however that's just a guess - if anyone has a better idea i'm all ears (just keep in mind i'm working from a terminal and don't want GUIs)
I use the Tag Sanitiser to remove all the junk tags from my files:
https://www.foobar2000.org/components/view/foo_sanitizer
i'm on Linux, so no foobar2k (i don't use wine either)
plus i'm using console tools because rebuilding mp3s is part of a larger shell script project
What exactly do you mean by "LAME tag"? Artist, etc. is all IDv3. Do you mean the vendor string?
LAME tag is identical to the Xing VBR header, except with a different signature which is used for CBR files.
yes, i think
@kode54 explained what i meant
when LAME encodes, it "extends", if that's the right word, the Xing header - in it is some info about the mp3, particularly a CRC checksum of the audio stream and it is this i am most interested in keeping when rebuilding the file with ffmpeg
You could try and add
-codec:d copy
to your command line
-dcodec copy
should also work
hi
@Maggi - thanks for the reply
that didn't work for me ...
Unable to find a suitable output format for 'dcodec' dcodec: Invalid argument
Unable to find a suitable output format for 'codec:d' codec:d: Invalid argument
regardless, i suspect that what i'm trying to do may simply not be possible
the LAME tag is part of (or is, or replaces) the Xing header and so i suspect that it cannot be separated from Xing which means i'd have to map/copy the whole header, which i don't want to do because i want ffmpeg to write a fresh one
so unless there's an ffmpeg stream specifier for only the LAME tag (i couldn't find it), i think i'm up the creek and i think what
@kode54 said confirms that it's either all (Xing/Lame) or nothing
as much as i'd like to keep the LAME CRC checksum, i don't think it's possible
That error message looks like you forgot to put a - before those options
dcodec copy vs. -dcodec copy
codec:d copy vs. -codec:d copy
:)
I just made a few tests and if you use
ffmpeg -i "%~1" -map 0:a -acodec copy -dcodec copy -bitexact "%~dpn1_out.mp3"
-map 0:a will only map the audio stream, so the album art will not get transfered to the output file.
The rest of the metadata seems to be unaffected and passed (copied) to the output file.
You could extend that command line to explicitly strip certain tags using this table
https://wiki.multimedia.cx/index.php?title=FFmpeg_Metadata#MP3
eg.
-metadata album="" will delete the album tag
-metadata artist="" will delete the artist tag and so on
ffmpeg -i "%~1" -map 0:a -acodec copy -dcodec copy -metadata album="" -metadata artist="" -bitexact "%~dpn1_out.mp3"
8)
Try this:
ffmpeg -i /path/to/input.mp3 -c:a copy -id3v2_version 0 /path/to/output.mp3
@nu774 - that sort of works in that there is a LAME tag copied to the new file and the metadata i don;t want is discarded, but some of the LAME data is altered - here i'm looking at the files with mp3guessenc...
original
Bitrate strategy : CBR, 255 kbps or higher
Lowpass value : 20500
nspsytune : yes
nssafejoint : yes
nogap continued : no
nogap continuation : no
ATH type : 4
Encoding mode : joint stereo
Source frequency : 44.1 kHz
Preset : 320 kbps | copy
Bitrate strategy : unknown
Lowpass value : unknown
nspsytune : no
nssafejoint : no
nogap continued : no
nogap continuation : no
ATH type : 0
Encoding mode : mono
Source frequency : 32 kHz or below
Preset : No preset. |
but then when i look at the MPEG stream details, the info is correct...
Data rate : 320.0 kbps
Audio frequency : 44100 Hz
Encoding mode : joint stereo
so i ended up with conflicting info and i'm not sure how different decoders would handle that
That error message looks like you forgot to put a - before those options
i messed up when i made that post - indeed i did forget the '-' at first, but i then corrected my mistake, then forgot i corrected it and posted the erroneous errors
both of your suggestions provide a very similar result regarding the LAME tag - the above is using
@nu774 code
i really appreciate the help but i don't want to keep beating a potentially dead horse either - perhaps i should discard the LAME tag as i was originally doing and not worry about it, or dump the specific metadata i want to remove
from a decoder perspective, are there any consequences to discarding the LAME info?